With the click of a mouse, Cale Vanderveen swoops through the Yonge Street canyon, then pivots around the CN Tower, past the top of the proposed casino complex.

The 17-year-old high school student from Uxbridge is demonstrating a 3-D model of the downtown core that he built on his laptop using SketchUp, free modelling software formerly owned by Google.

The proposed buildings are constructed in SketchUp and placed in a model of present-day Toronto from Google Earth. The result is an interactive 3-D model that shows just about every future structure in the works, from the newly announced Gehry-Mirvish towers on King Street West to those well under construction, each building colour-coded to show its stage of development.

"It's just a hobby that's exploded," he says, laug

A flyover video tour of the model Cale put up on YouTube is a glimpse of the project that took him about three months to construct in his spare time.

"I guess I just wanted to visualize the city," he says of his hobby.

The aspiring architect became fascinated with the Toronto skyscraper boom about two years ago, using online forums such as Urban Toronto and Skyscraper Page. When he saw the plans for the Trump Hotel, he decided to use SketchUp to project what it would look like.

Then he moved on to waterfront development, and continued until he'd mapped the entire downtown core -- with a bit of Yonge and Eglinton to the north and Humbertown to the west.

The model is not perfectly accurate, says Cale. He gets most of his data from building permits and development applications available through the city's Open Data program. Sometimes he estimates pieces from developer marketing images.

Even so, "it's very impressive," says Frank Lewinberg, a partner at planning and design firm Urban Strategies. "Anything that encourages public awareness and engagement with what's happening in the city is a wonderful thing."

But sharing Cale's visualization of what the city is becoming is a challenge. The model exists only on his computer, made public only through that virtual tour video.

The same is true for the City of Toronto building model, a behemoth begun in 1987 in a program called MicroStation. It now features 100,000 of the city's one million structures, shown in painstaking detail, down to the slopes and dips of the terrain, says Carolyn Humphreys, program manager of the city's graphics and visualization department.

Meanwhile, for Cale, the near future is looking up. Interest sparked by a Canadian Business blog post about his model last month won him a summer job at RealNet, a real estate investment research company.

"It's just a hobby that's exploded," he says, laughing. "It's kind of cool."